/*

* Copyright (c) 2006 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* which accompanies this distribution, and is available

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Interface for implementing custom ordering for tree list.

*

*/

#ifndef M_AKNCUSTOMTREEORDERING_H

#define M_AKNCUSTOMTREEORDERING_H

#include <akntreelistconstants.h>

/**

 *  Interface class for implementing custom ordering for hierarchical list.

 *

 *  Implementation of this interface class can be set to hierarchical

 *  list to define the ordering of items in the list. Hierarchical list

 *  then uses the implementation of @c MAknCustomTreeOrdering::Compare

 *  method in sorting the items within each node of the list.

 *

 *  @since S60 v3.2

 */

class MAknCustomTreeOrdering

    {

public:

    /**

     * Compares two tree list items.

     *

     * @param aFirst Item ID of the first compared hierarchical list item.

     *

     * @param aSecond Item ID of the second compared hierarchical list item.

     *

     * @return Positive, if the first item is greater than the second item;

     *      negative, if the first item is less than the second item;

     *      and zero, if the items are equal.

     */

    virtual TInt Compare( TAknTreeItemID aFirst, TAknTreeItemID aSecond ) = 0;

    };

#endif // M_AKNCUSTOMTREEORDERING_H